So one day I had my girlfriend come over and hung out well as things start to settle in we wanted to try something new,anal sex. But I guess I was to into the mood that I rubbed my penis on her anus and I kinda stuck the tip in but got it out right away. Can I catch an infection from this?, please help me out Im really worried to be honest.
With all due respect, when you say you decided to start having anal sex, what exactly did you think was going to happen? Anal sex generally means that a penis is going to go inside someone's anus. It doesn't have to mean that -- certainly vibrators and toys can be used for anal sex as well. But overall when two or more people get together with the intention of having anal sex, and one or more of those people have a penis, it means someone's butt is likely going to be penetrated by said penis.
So you stuck the tip of your penis inside her anus, as one does when having consensual partner. I'm wondering why you got out right away? Was that a decision she made? If this was her first time, she may not have been prepared for the initial 'burn' that sometimes accompany penetration when starting anal sex. Or did you pull out because you were afraid of disease? Which kind of brings me back to my first question above...
Anyway, your question seems to be about catching an infection from quick penetrative anal sex. You don't mention if a condom was used, so I'm going on the assumption it was not. If your girlfriend had an STI inside her butt such as gonorrhea, chlamydia, or syphilis, it theoretically would be possible to give it to you. But the STI (sexually transmitted infection) would have to have gone from inside her rectum into your urethra. One quick dip is very unlikely to result in that kind of travel. And, if you read this column regularly, then you already know that the likelihood of you acquiring HIV from quickly inserting your penis anywhere in anyone is nearly zero.
It's also important to remember: If your partners don't have infections, they can't transmit infections. You don't mention if you have any reason to believe your girlfriend has any rectal STIs but if you think she might then it makes even more sense to get tested.
Of course we could speculate on all kinds of scenarios here, but you're really not going to know anything for sure until you get tested. Most STIs show up within a couple of weeks so I would wait and then ask for a test and a clinic or healthcare agency. That is truly the only way your question can be answered satisfactorily.
In the meantime, talk to your girlfriend, discuss your concerns. If there's no reason to believe she has any STIs, then why not go with that? And if she wants to experience anal pleasure with you, why not share that with her without pulling out right away? Anal sex can be a wonderful way for humans to connect when two (or more people) choose to share their bodies that way. But it's important for them to communicate, find a 'safe word' for stopping, and get tested regularly for STIs. Enjoy!